Faculty Bibliography

Background: Footwear has a profound effect on walking speed, and lower extremity kinematics and kinetics. The purpose of this study is to identify possible predictors of walking speed and stride length in high- and low- heeled footwear. Methods: Thirty-one female subjects, each of whom were screened for lower extremity pain or dysfunction, and were determined not to be regular users of high-heeled shoes, participated in this study. Standardised, appropriately sized low- and high- heeled footwear were provided for all subjects. Euler angles were used to calculate the motion of the distal segment relative to the proximal segment. An inverse dynamics approach was used to calculate the net joint moment and power at the ankle, knee and hip joint. A paired t-test was used to assess the effect of footwear, and stepwise linear regression was performed to identify possible kinematic and kinetic predictors of walking speed and stride length. Results: Use of high-heeled footwear resulted in slower walking speed and shorter stride length. Regression analyses indicated that the most significant predictors of self-selected walking speed in high-heeled footwear were sagittal power generation at the knee, hip flexion, and sagittal power absorption at the ankle. Determinants of stride length when walking in high-heeled footwear included ankle sagittal power generation, hip sagittal range and the hip extension moment. Conclusion: A relatively simple model (three predictors or less) was able to explain 30-60% of the variance in walking speed and stride length. The key findings of our study underscore that altering heel height results in a change in motor strategy and attendant joint contribution used to maintain walking speed and stride length.

BACKGROUND:Low arch alignment and metatarsus primus elevatus (MPE) have been postulated to increase dorsal compressive stresses in the joints of the medial column of the foot and to contribute to the development of degenerative changes. The primary purposes of this study were (1) to examine the relationship between radiographic measures of arch alignment and MPE and (2) to assess arch alignment and MPE in individuals with midfoot arthritis and in asymptomatic controls. The secondary aim was to examine the reliability of radiographic measures of arch alignment and MPE. METHODS:Radiographic measures of arch height and MPE were quantified on 28 individuals with midfoot arthritis and 22 individuals in a control group. Reliability was assessed using the intraclass correlation coefficient (ICC). The Pearson product moment correlation (r) was used to assess the relationship between arch alignment and MPE. Between-group differences were assessed using a two-sample t test (α = 0.05). RESULTS:Good to excellent reliability was noted for measures of arch height (ICC[2,3] = 0.919-0.994) as well as MPE (ICC[2,3] = 0.891-0.882). A modest positive association was noted between normalized cortical elevation and normalized navicular height (r = 0.274, P = .030) and calcaneal inclination angle (r = 0.263, P = .035). Individuals with midfoot arthritis demonstrated lower arch alignment, reflected in a significantly higher calcaneal-first metatarsal angle (P = .002), lower calcaneal inclination angle (P = .004), and lower normalized navicular height (P < .001) compared with controls. No evidence was found to support between-group differences in lateral intermetatarsal angle (P = .495) and normalized cortical elevation (P = .146). CONCLUSIONS:These findings provide objective data establishing the reliability of measures of MPE and arch alignment and their potential clinical significance.

The purpose of this study was to compare estimates of gastrocnemius muscle length (GML) obtained using a segmented versus straight-line model in children. Kinematic data were acquired on eleven typically developing children as they walked under the following conditions: normal gait, crouch gait, equinus gait, and crouch with equinus gait. Maximum and minimum GML, and GML change were calculated using two models: straight-line and segmented. A two-way RMANOVA was used to compare GML characteristics. Results indicated that maximum GML and GML change during simulated pathological gait patterns were influenced by model used to calculate gastrocnemius muscle length (interaction: P = .004 and P = .026). Maximum GML was lower in the simulated gait patterns compared with normal gait (P < .001). Maximum GML was higher with the segmented model compared with the straight-line model (P = .030). Using either model, GML change in equinus gait and crouch with equinus gait was lower compared with normal gait (P < .001). Overall, minimum GML estimated with the segmented model was higher compared with the straight-line model (P < .01). The key findings of our study indicate that GML is significantly affected by both gait pattern and method of estimation. The GML estimates tended to be lower with the straight-line model versus the segmented model.

Musculoskeletal conditions of the foot and ankle are an important public health challenge due to their increasing incidence combined with their substantial negative impact on patients' quality of life. Non-pharmacological treatments serve as the first line of treatment and are frequently used for patients with musculoskeletal conditions of the foot and ankle. This review provides a summary of the assessments and non-invasive treatment options based upon available evidence. Recent studies show that individuals with foot and ankle pain have multiple co-existing impairments in alignment, motion, load distribution and muscle performance that may be evident in static and/or dynamic tasks. In addition, both clinical and epidemiological studies support the inter-dependence between the foot and proximal joints. For instance, aberrant foot structure has been linked to foot osteoarthritis (OA), as well as OA and pain at the knee and hip. Most recently, advances in motion capture technology and plantar load distribution measurement offer opportunities for precise dynamic assessments of the foot and ankle. In individuals with musculoskeletal conditions of the foot and ankle, the chief objectives of treatment are to afford pain relief, restore mechanics (alignment, motion and/or load distribution) and return the patient to their desired level of activity participation. Given that most patients present with multiple impairments, combinational therapies that target foot-specific as well as global impairments have shown promising results. In particular, in individuals with rheumatoid arthritis and other rheumatic diseases, comprehensive rehabilitation strategies including early detection, foot-based interventions (such as orthoses) and wellness-based approaches for physical activity and self-management have been successful. While significant improvements have been made in the last decade to the assessment and treatment of foot and ankle conditions, few randomised clinical trials specifically have investigated patients with foot or ankle conditions to provide global insights into this area. Consequently, current recommendations vary based upon the scope of studies presented in this review as well as the strength of studies. This review indicates a need for more in-depth investigations into the components of assessment and treatment options for foot and ankle musculoskeletal conditions.

Regional plantar pressures during stair walking may be injurious in at risk populations. However, limited data are available examining the reliability of plantar pressure data collected during stair walking. The aims of this study were three fold; to assess the reliability of the plantar pressure data recorded during stair walking, to assess the effects of level ground and stair walking on plantar loading, and to develop regression equations to predict regional plantar pressures in stair walking from those collected on level ground. Fifteen subjects without conditions affecting their ability to walk on level surfaces or stairs were recruited. Each participant performed at least 10 steps in level ground and stair walking while plantar pressure data were recorded in six foot regions. Reliability was assessed using Intraclass Correlation Coefficient. A repeated measures ANOVA was used to assess the effect of activity on plantar pressure, and a linear regression was used to predict forefoot loading during stair walking. A reliability of 0.9 was achieved within 10 steps in all foot regions, with the forefoot requiring fewer steps. Plantar pressures were influenced by both, foot region and activity, with the heel and forefoot regions generally experiencing lower peak pressures and maximal forces during stair walking than level ground walking. The regression equations predicting peak pressure during stair walking accounted for between 37% and 70% of the variance of the stair walking data. These findings establish the reliability of plantar pressure data collected during stair walking. Future studies should investigate these parameters in clinical populations.

BACKGROUND: Knee pain and early arthrosis have emerged as significant problems in young adults with myelomeningocele (MMC). The purpose of our study was to examine kinematics and kinetics during gait in symptomatic and asymptomatic limbs of children with an MMC to better understand the factors that may predispose individuals with an MMC to potentially debilitating knee problems. METHODS: Seven children with L3-L4 level MMC and 8 age-matched typically-developing control children participated in this study. Three-dimensional kinematic and kinetic data were obtained bilaterally during gait. A custom-designed femoral tracking device, with established reliability and validity was used to track the thigh. The limbs in an MMC group were subdivided into 2 subgroups (n=6 and 8, symptomatic and asymptomatic, respectively) based on history of pain at the knee joint after walking/weight bearing activity in the last 6 months. An 1-way analysis of variance with post hoc Bonferroni adjustments was used to compare lower extremity kinematic and kinetic variables between symptomatic, asymptomatic, and control limbs. The Pearson product moment correlation (r) was used to assess the relationship between variables of interest. RESULTS: Symptomatic limbs showed increased knee flexion in stance (P=0.01) compared with asymptomatic limbs. Symptomatic limbs showed trends toward increased knee extension, adduction, and internal rotation moments (P=0.031, P=0.025, and P=0.024, respectively) compared with asymptomatic limbs. Hip internal rotation was positively associated with knee internal rotation moment (r=0.93, P=0.008 and r=0.76, P=0.08 in symptomatic and asymptomatic limbs, respectively) and increased knee adduction moment (r=0.84, P=0.03 and r=0.91, P=0.01 in symptomatic and asymptomatic limbs, respectively). CONCLUSIONS: Symptomatic limbs in children with an MMC showed increased knee flexion and trends toward higher extension, adduction, and internal rotation moments. Increased knee flexion accompanied by inadequate control of hip transverse kinematics may have significant implications for knee joint loading in this population. LEVEL OF EVIDENCE: Level 4 (Case series with controls, motion laboratory gait analysis).